There is no such things as commercial GMRS, it's business band or it's GMRS (in this case, business band).
I've never heard of a radio which can work on 463/468 and not also on 460/465 and 453/458 (the two nearby public safety bands). A while ago some models came in UHF and UHF-T models, but even that has generally been broadened to something like 400-470 and 450-512. Anyway, I doubt the cost of radios was a reason why they went with business band instead of public safety. As far as the FCC is concerned (and disregarding common sense and NFPA and similar requirements), the same cheap radio marketed for business use on 463.825 could be used on 453.825.
Around me public safety channels are a lot more of a pain to get than business band. I'm not even sure how much is available -- I've heard that most UHF and 800 public safety channels have been let out so getting a new channel involves all sorts of waivers and consent from cochannel licensees. I can't vouch for that but I do know that typically very soon after a PS channel is abandoned by one town for a trunked system, it is gobbled up by another.
Jim