Pam--I feel your pain. I was supposed to get a large "Sewing Studio" but that is not going to happen now--thanks to our builder friend--I should say my X-friend. I had done up plans for "OUR" remodel with an enlarged garage to fit both cars. I love my house but the 2-Car garage is small. Anyway, the builder finally said he did not want to spend my husband's money--WHAT??? It is my money too. My next plan was to do what you want to with our garage and build a seperate garage for our cars and his tools, etc. Now my husband says he is getting too old to even do that.
The main reason for me wanting to do this is I have an online business that is growing--thanks to this wonderful group and I need more room for more bolts of fabric ;-) Right now everything is in our walk-out basement and I am taking up my computer room, Great Room, 1 guest room and under the stairway. It is difficult for me to have customers come out the way I am set up now and with the Quilt Shop in town closing it would have been a perfect opportunity for me and would have been very nice for the town's quilters.
Good luck--I hope you are able to do what you want.