There isnt a rom that has SPB. I know, cuz I've tried most, as I'm a big SPB user. I rolled a rom at one point, but I never got MSVC working in rom.
As to where your msvc.exe is, you can look in your hard drive, c:\program files\microsoft activesync for cabs or related folders. (not on a machine with AS on it...) There should be a cab for msvc, and you should be able to open the cab, find the exe and save it on your phone... well, its a bit more complex than that... I'd suggest searching the forums or asking someone in the chat that can get you hard info...
If you really want SPB in rom, I'd suggest learning how to download the kitchen and roll your own. It's really not that hard, and almost impossible to brick your phone, but you will need to hard reset and flash some stuff. I'd suggest doing lots of reading here and chatting on our chat.
As to your "from what I have read" line, you're dead on. However if you are using a custom rom, you probably want to soft reset at the "3 seconds til customization" and dont let the extrom run, as it usually installs files that conflict with the newer version of the AKU (think of AKU as "windows updates for ppc")
Hope this helps more than it confuses.
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