Three Tees - I share your frustration - both with the lack of 3d gen lasers and the aging eyeballs. This thread
Crimson Trace Lasergrips for 69xx, 39xx & CS9 describes what I went through to modify the Crimson Trace lasers for my 6906, 908 and CS9. I don't have any 40's or 45's to fit the CT laser to, but I think the LG359 for the 59xx series can be made to fit them. Not a project to be taken lightly, though.
The only alternative I know of is the (I think) Lasermax which replaces the rear sight. I've heard several people say they like them and several that they didn't like them - only you can decide.
Let us know what you figure out.