Yeah, definitely don't gut the SF1 cab, that's a classic... Golden Tee 98 somewhat too, but it wouldn't be as much of 'crime', haha.
I'm telling you, just get a good tube tv on Craigslist for $50, hit up DiveMaster for all your parts (he'll save you an a$$load compared to buying direct, literally saved me about $200), and get some fiberboard. I was gonna cheat, I bought a pre-gutted cab but when I got there to pick it up, aside from it not fitting in my SUV, I really got a little 'weird' about it, almost sad (as pathetic as it sounds) that I wasn't going to at least try.
It's been so much fun so far figuring all of this out and in the end, I'll better know the in's and out's of the process and all that. You can do it cheap for about the same price you'd buy an original cab for and hold your head high knowing that you created the masterpiece that you get to game on.
Still, pick up one of the original cabs to put next to your Mame cab, but still, don't cheat yourself out of the experience.