We can do that and I would also personally appreciate it in 3/8ths, I use a 12x12 in 3/8th because I do, like you, mostly .308 and down. The 3/8 12x12 is about 6 lbs lighter then the 1/2 of the same size. If you want I can put your name down for a 3/8th idpa target. Just can't say with 100% certainty when we are going to buy 3/8ths as for some reason it isnt as popular.
Thanks for taking the time to tell us what you would like to see.
Cheers - Matt