What questions should I ask a general contractor, who will be doing a conversion from a bath shower conbination to a full tiled walk-in shower. Thanks for any input.

Actually you need to write down what you want, not what he plans to do. You need to decide if you want a custom shower pan built from scratch, a retor fit shower pan that fits a tub foot print or a factory acrylic shower pan. Most generals do not know thing #1 about building a custom shower pan, maybe their subs will. How to Build a Shower Pan (http://hoagy.org/house/HowToBuildShowerPan.html)

I replaced a tub with a shower. I used a retrofit shower pan. Kohler and Swanstone carry them. I ordered mine through Home Depot(Swanstone) and am very pleased with it. I had to change out the drain from 1 1/2 to 2" and move the shower valve up to a height I felt comfortable with. Do your research and find something you like and don't let them take any short cuts.
HGTV : Decorating, Remodeling, Home Improvement & Gardening Ideas, Videos and more : Home & Garden Television (http://ratemyspace.hgtv.com/snc/EditGroupList.aspx?pguid=6db6be3f-1720-4ba3-a081-999042c09b6b&itemguid=ed828272-d74e-4921-8086-486297f7f413)

Bathroom Remodeling Pictures Design Tile Ideas Photos Shower Fairfax Manassas Va. (http://www.danielskitchenbath.com/bathroomphotos.html)

http://www.plumbersurplus.com/Cat/Shower-Floors-Shower-Pans/764/List?attribute_value_string%7CBrand=Kohler

http://swanstone.com/index.php?cat=4&attr=78