Yes, its all about what you are wanting to achieve in the end and how you want to go about it.
A Prophet Desktop would be sick, but the sonic capabilities would be limited compared to eurorack. Id even go so far to say the Make Noise 0 Coast would give the Prophet a run for its money with flexibility and fun factor.
The Prophets sound sick and is obviously a beautiful synth to own, but in my opinion it depends how much Prophet sound you want in your productions or have excess money to waste on hardware. For me personally the Prophet would be great Techno, Ambient, Chill or old school John Carpenter style stuff.
Im not sure what the "BSP" is, but another option for you could be the Erica Synths Pico range, which is another little modular system.
(1) DNQAAOSw44BYV~k0" target="_blank">http://www.ebay.com.au/itm/Erica-Synths-Pico-Eurorack-Case-Power-Supply-42hp-/162326609458?hash=item25cb6b7e32DNQAAOSw44BYV~k0
(2) WOMAAOSwZQRYZxvV" target="_blank">http://www.ebay.com.au/itm/Erica-Synths-Pico-VCO-Oscillator-EURORACK-NEW-PERFECT-CIRCUIT-/302182229411?hash=item465b76e5a3WOMAAOSwZQRYZxvV
On the more expensive side of things, there are some similar options available such as:
(1) Roland System 500
(2) Pittsburgh Modular Lifeforms System-201
(3) Sound Machines Modulor 114
You just have to spend enough time browsing companies products to know whats out there.
Some recommendations for Cases would be:
(1) Doepfer A-100P6
(2) Doepfer A-100LC9
(3) Doepfer A-100LC3
(4) TipTop Audio Mantis
(5) Any kinds of 3U Skiff Case combined with a TipTop Audio uZeus PSU and power brick.
Heres a example of Skiff case that comes with a PSU:
(a) http://www.ebay.com.au/itm/302018843188?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
(b) http://www.ebay.com/itm/Synthrotek-Cheeks-Power-6U-104HP-Case-V1-EURORACK-NEW-PERFECT-CIRCUIT-/121962215659?hash=item1c6583b8eb
(6) Synthrotek also offer alot of cool stuff in regards to cases and psu's:
(a) http://www.ebay.com/itm/Synthrotek-Cheeks-Steel-6U-84hp-Case-EURORACK-NEW-PERFECT-CIRCUIT-/302126540028?hash=item46582524fc
(b) http://www.ebay.com/itm/Synthrotek-Cheeks-Steel-9U-84hp-Case-EURORACK-NEW-PERFECT-CIRCUIT-/302126540343?hash=item4658252637
(7) Something from SynthRacks.com
(8) Go down the custom case route by either buying side panels or making them yourself:
(a) http://www.ebay.com/itm/Erica-Synths-WOOD-SIDES-1x-6U-THICK-Case-EURORACK-NEW-PERFECT-CIRCUIT-/301730320410?hash=item464087501a
Buy the rails, screws, threads or sliding nuts and PSU aswell. But you need to consider to time of labour and what kind of tools you will need. Going down the pure custom case route isn't always the best option for people who do not have easy access to tools etc. Plus you would only end up saving about $200 - $300 compared to some of the options above, which is basically 1 new eurorack module, is all that effort really worth it to you ?
Hope this has helped
Goodluck