teca99,
In your original post you state that you can't shell out more than $1000, but want room for customization.
For just under $1000 you can probably take your pick (get one that has everything you want or get a basic model and add everything you want).
You can get one of the Kimbers or the Springfields that has all the features you want, or you can buy a "mil-spec" and add parts as you like. If you buy a good brand, it should last a long, long time.
I guess what I'm trying to say is for the money you are willing to spend you wouldn't need to leave room for customization (unless you want real fancy), you could just buy everything you want right off the bat. If you do want to tinker and add parts, you can just get a mil-spec.
The word "Custom" as you are probably seeing it (Kimbers) doesn't mean the gun isn't mass produced. Kimber named their guns Custom because when they initially started producing 1911s they had features normally associated with customized 1911s.
You really could do well with a Kimber or a Springfield.
Shake