It's a lot of work to have to pay someone to do it (expspensive) You could save a lot of money and do it yourself: I'm not to sure on the difference between Bay and split beam's.
Here is the beam that we built for my 67, I would start by doing some research on the samba in the Bay forum's and go from there: I dont know of any shop's in Houston that would do it for you but then agian I havent lived there in a few years and I could be wrong!

It is 4" narrowed and adustable, add drop spindles on top of that and you could get pretty low, the sky is the limit: or I should say the ground, but bus stuff is pretty much all custom and takes a lot more patience!