Truth be told, I've never owned a fightstick in my life. Is it hard to install one of these MC Cthulhus or is there much risk of breaking the stick itself? And where is a popular site to buy the MC Cthulhu board?
I personally don't know how difficult it is to install. There are models that are preassembled and have screw-down terminals instead of needing to solder, but they are more expensive. You also have to make some modifications to the case, so that would require a little dremel work. There is a great tutorial on SRK
for the SE stick that better explains the process.
As for getting the board itself, Modchipman.com is generally pretty reliable with shorter shipping and handling times than most sites. Here is some more information and pricing.
This particular set comes with an IMP board, which makes it possible to switch between consoles without having a toggle.
On the other hand, if you don't mind waiting for 3-4 weeks and putting a little more effort into the project you can try Lizardlick.com. You can get an unassembled PC/PS3 ONLY Cthulhu here
for around $20 + shipping.