i read on various forums for modular synthesists and they always seem to discourage people from getting a small rack, like the Doepfer mini case or Synthrotek Power Lunch etc. They say its a waste, get a bigger case, you will need it, you will want it to be bigger...
What I REALLY want IS something kinda small, that I can wrap my head around. I'm currently using a Moog DFAM, Microbrute, a couple Volcas and some effects. What I would really like to try is a small case with Pamela's New Workout, Expert Sleepers Disting, Synthesis Technology E950, and a couple VCAs and ENV generators as needed... wouldn't this cover at least a few bases, for a beginner? Then if I DO want to expand, and I suddenly have more space and a bunch more money... I guess that is what they call a GOOD problem to have, right?
Am I missing anything important?

I don't see any problem there, nope. I discourage people from getting a small rack if they're beginning with this because it's a good idea to have a broad-based starter rig when you first get into modular. But when someone has a specific musical concept in mind and they know it'll work best in a smaller form factor, then by all means go for it. And given that you're running a DFAM already, snagging two more 60 hp Moog cabs (watch your module depths!) for a total of 120 on which to expand the DFAM makes a lot of sense. Moog's designers already thought of this by offering their matching cabs and double and triple racks. Slap a couple of uZeuses in those and get busy!

One thing, tho...given that you're building this up around a DFAM and thinking of adding a Pam's to that, also consider a couple of things to deal with clock modulation and logic. That way, you can patch up all sorts of timing strangenesses that key off of counts (dividers and multipliers), CV (comparators, derivators, etc), pulse manipulation (width controls, clock delays) and randomfactors (probabilistic skippers, etc). Ladik makes a number of these that fit into 4 hp each, and Doepfer has their divider and ratcheting multiplier, and there's a few companies that offer nice, space-thrifty Boolean operator modules. May as well make that sequencer turn some cartwheels if you've got the space for a few of those.

Thank you very much, that was the kind of advice I was needing. I was looking into the Moog racks but I was concerned about depth. And I don't understand why they are so inexpensive... I realize they don't have power, but I look at how much a power supply costs and I can't figure how an unpowered case goes for $50 and a powered case goes for $350.
Also, did you mean to suggest those other modules INSTEAD of the Pam's , or to add to/augment the Pam's? Good info, tho thanks again.

Definitely to augment. Consider the following:

Take two Pam's outputs. Run one to one side of an AND gate, and the other to the other side. Then take your modified timing signal out of the AND gate's output. What will happen as a result is that the gate will only send a gate signal when there is a 'high' state (ie: gate on) present at both inputs. So unless the Pam's outputs a gate at the same time on both channels, no gate gets sent to whereever it's patched. By doing lots of these little tricks, plus adding things like gate delays, skippers, swingers, dividers, multipliers and so on to screw around with the 'raw' gate signals, you open up a big box of polyrhythmic craziness that wouldn't normally be doable without those + some logic. Or...let's say you have a pattern running on Pam's, but it should only pass when stage #6 is active on the DFAM. Set the DFAM's 'velocity' row to only output voltage on #6 (the rest of the row has the pots all the way down), patch 'velocity' to one side of an AND gate, and the Pam's pattern to the other side. So...when the 'velocity' CV is present plus the pattern at the AND inputs, the pattern gets through the gate...but only while step #6 is active. So, yeah...lots of fun like that, which can really open up loads of interaction between sequencers, rhythmic elements, etc. Use your imagination; I'm sure you can come up with loads more ideas!

I think small cases are good for specific jobs... I have all my drums in a Dopfer mini case .
Convenient if I just want to take the synth case and say use a sampler instead of the modular drums.

When you buy a module... the Lugia Law of modular states you'll want to buy another one.

Starting out in a skiff means you're going to box yourself in in no time. There are tons of great modules out there but are exclusively in larger HP forms. If you put a couple of these larger beasts in your rack, you quickly run out of room. Having to slave your next purchase based on available HP puts a serious ding in your set-up when first starting out.

I think the Tip Top Mantis offers 208 HP (104HPx2) for around $300US. I would start in something like that. The balance between price and space seems about right.

I went with the Intellijel 7U 104 case (then bought another one). I still weigh the pros and cons of my decision... but I really wanted the 1U for attenuverters (Intellijel Quadrats). Inverting CV, mixing, etc... I paid the premium to have that.

Yep. Go big, or go..........out and buy another cab! ;)