Welcome! I bet most people here probably just want one, just trying to find it. I have 7 and two builds in progress, still haven't decided. Interested to hear about your plans to mod the unicomp. Have you tried the Model F though?
I haven't tried the model F, though I've read that it has an even better feel than a model M because of the flippers hitting the PCB. I've had a look at the project to reissue the model Fs and it looks amazing. I just can't quite justify the $300 right now on a mechanical keyboard (plus, I wanna get my hands a bit dirty and learn a bit more). That F77 looks so nice though!
My interest stems from the combination of building my first computer and trawling subreddits for everyday carry and pens/pencils (where a surprising number of mechanical keyboards popped up in photos).
Not as much into "EDC" as such, but I've collected fountain pens for years. (And I found the Karas Kustoms fountain pens are very solid with EDC style too.)
I've also been a Mac user for many years, so here are some suggestions for you to look into. . .
The Unicomp Spacesaver M is a Mac layout, and it's the only keyboard I've seen that comes with a Fn-lock feature. Which is to say. . . You can hit Shift-Function and toggle between the top row working as F1-F12 or as media/expose/dashboard keys, and there's even a Fcn indicator light. Convenient! However, the Unicomp is a sort of creaky-and-clunky beast, not the premium experience that some might imagine of the "legendary" Model M. Not sure what mods you had in mind for it -- maybe that's something I need to look into? I've used my Unicomp for the last roughly five years until the controller died, then Unicomp fixed it and cleaned it up like new. It's the antithesis of Apple semi-disposable keyboards!
That does sound pretty convenient! I've recently migrated to Ubuntu on my home desktop but still have my macbook that I dual boot from and take with me to the office. I wasn't sure that I was going to like the switch (it's taken some getting sued to) but I love the customizability of it. We'll see how I feel after more prolonged exposure.
As for the modifications, I started up a thread here:
https://geekhack.org/index.php?topic=90693.0 that sort of outlines what I'm looking to do. Everything I've read backs up your point about the build quality being lower on the Unicomps than the model M, continuing the trend of making things lighter and less expensive (thinning the metal backplate, etc.). I think ideally I'd want a metal case like those of the model Fs that have a decent sized bezel and that I could powder coat to get some of that beautiful texture. Next to that, a model M would be great. Unfortunately I don't really want to mess something that nice up while trying to work my way through a build when I have few skills! We'll see what happens, but I'm in the process of looking around thrift shops and garage sales to find a model M that I wouldn't feel bad about hacking up.
I haven't ever tried a Matias, but they use ALPS-style switches and have a lot of Mac-specific keyboards in their catalog. They even have a "mini" Bluetooth keyboard with their new silent switches. Might be worth looking into.
I'll have a look. I'm also keeping my eye out for one of those old Dell keyboards with ALPS switches that would be a nice trial board for making TKL and getting acquainted with the process.
The more premium mechanical keyboards tend to be either switchable to a Mac configuration or fully programmable. The WASD is configurable using DIP switches. The WhiteFox is programmable. The new production Model F keyboards are programmable.
That's something that I find really cool. I've never really spent a lot of time looking into developing macros and reprogramming my keyboard but since getting more into this, it's become something I'd like to check out.
As for only wanting one, well. . . We shall see, we shall see. 
)
That's what I'm afraid of!
