Well, in particular, I'm interested in how you modded the tricorder... but I'm sure others might want to know about your other upgrades.
The tricorder mod was pretty easy. Started with a stock DST Medical Tricorder with paint runs, fingerprints and glue smears, pretty standard for many of these! Took it apart, sides snap off and rest comes apart with screws. Some parts cemented together. Gutted the electronics, didn't like them and I think that sound fx and such turn prop replicas into toys. I was trying to turn a toy into a prop replica!
The viewscreen/control panel faceplate was a bit difficult to get apart. The original is cemented together. Now I knew I was replacing it so I didn't mind getting rough with the original screen and panel. If one was going to disassemble it for a quick repaint and wanted to re-use those parts they would have to work very carefully...
I made a new, more accurate control panel from sheet styrene. The viewscreen is made from a 2-liter plastic Diet Coke bottle. Near the top of the bottle is a section that seems to have an appropriate compound-curve. Painted the back of the new screen grey and installed it from the back of the panel. The T-Jet knobs are aluminum replicas made by Dennis Stines. I made the watch crowns in resin from a mold I made off of an original. My blue saphires are turned and painted styrene rod. The mic screen is from a vintage 1960's transistor radio.
The black "replica kydex" parts were painted with satin Krylon black. I cleaned up the silver frame, had to remove a lot of mold parting lines and some flash. Then the silver was painted with Tamiya gloss aluminum.
I did replace (and re-position) the moire ring using a ring I had in my parts-box (another Dennis Stines part). For lack of anything better, I did re-use the DST moire, but not the motor. A new leather strap and a couple of screws complete the re-assembled tric.
I don't think the silver paint will be tough enough to stand up to a lot of handling, but this is strictly for display so it will do until I get around to building a better tricorder with real kydex and aluminum.
The phaser upgrade was similar. Took the toy apart, gutted the electronics, filled seams, replaced a lot of parts with metal that I've collected over the past couple of years and put it all back together after painting.
The Alpha comm was put together with a series of parts that Dennis Stines ran last year. It is a very accurate replica (you can read up about this project at the Trek Prop Zone) and is really the center piece in the collection. The Tricorder and Phaser will do until I upgrade to something better.
All in all this was a lot of fun and that's why it was worth doing. The DST tricorder really isn't worthy of all the work unless you're just having a good time at the workbench!
Marcus