I started a project like this with 40k Space Marines a few years back. It never took off (no surprise, since I already had armies coming out of my ears), but I always wanted to revisit it at some point. Getting into 15mm Sci-Fi and away from the 40k universe made it a bit less practical, but the desire was still there.
I also wanted to do a Hammer's Slammers centered around the excellent Old Crow minis. I picked up a Blower tank, a Combat Car, and a pack of Jeeps this summer, but never did decide on a paint scheme or what to use for accompanying infantry. I also picked up a few packs of NAC Infantry from Ground Zero Games earlier this year... same problem: I never knew how I was going to paint them or how they were going to fit into my various gaming worlds.
Inspiration finally hit me last week, and I painted a sample NAC rifle trooper in Nebraska Cornhusker colors. I liked it and decided to finish a squad, along with some vehicle support. Originally I was going to use the famous Matchbox SWAT vehicle for these, and only use this force in fun one-off games. After basecoating the SWAT vehicle, I noticed the Slammers stuff sitting on my desk, and figured hey, why not?
In my Conquest System game world, these will be a for-hire mercenary branch of the Aurora Corporation. Or if I would rather game in an established setting, there's no reason I couldn't use these as Hammer's Slammers right out of the book.
I have another eight NAC rifle infantry to add, along with a pack of the GZG one-man skimmers. Other than that I'll have to shop before I can expand this army. Looks like Old Crow and/or GZG are getting next month's gaming budget...