What about the "das keyboard"? I see there is a red switch version.
Well maybe i am looking for a keyboard that comes with doubleshots / metal backplate and such goodies by default. It is not that i do not like the filco, it is a great keyboard but where it lacks, are the caps (i have been using mine for about a year and the print is already fading...). I could buy the replacement caps, but my filco is ISO 105 and the good keycaps sets are rare to come by.
So i guees the only way to "upgrade" my experience is by going full custom.
First: Well, you like MX reds, but you don't like Topre? I guess you really like linear feel. Have you tried the RealForce Silent ergonomically-weighted keyboard? You will probably love the 30g Topre switches along the edges. They are like "puffy" reds. The have a like a "puff" of air feeling at the top of the keystroke (even though no puff of air actually comes out), and then they have a smooth linear feel for the rest of the keystroke. Some GH'er modified a Topre board to be all 30g, IIRC, so it's possible to modify a RealForce keyboard to all 30g.
Second: vintage blacks are very nice indeed. I can sell you a WYSE terminal keyboard with 105 vintage MX black switches from the early '90's. They are smooth as butter. PM me if you're interested. The old WYSE terminal keyboards have plate mounted switches, so you will have to desolder them to get them off.
Third: As for "upgrading" your user experience, I think it's time to start managing your expectations. By going full custom, you will spend a lot of money, and you may or may not be disappointed in the results. Going full custom will allow you to change the feel of the keyboard, by choosing plate mount, or PCB mount, metal case, PCB case, acrylic case, and then by choosing springs, lube and stickers. Also you can buy a controller to program to match your custom preferences, e.g., swapping Caps Lock for CTRL, etc. However all this will cost you at least $500, or more, and you will probably end up with a keyboard that is not noticeably better than your plain old Filco with MX reds. You might also end up with a switch-bouncing ping monster, if you're not careful in the execution of the build. Or you might end up with the greatest keyboard in the universe, I guess it depends on how much you fall in love with your own work. Anyway, I don't want to dissuade you from building a custom keyboard, since I think every GH'er should do it at least once, but just don't assume you are going to be building the ultimate user experience, just because it's a custom job.
Fourth: My last piece of advice is that before you jump into custom keyboards, your first step should be to get some new keycaps on that Filco. A new set of PBT keycaps, or even ABS double-shots will vastly improve your user experience with the keyboard you already own. Having faded and shiny OEM keycaps totally sux. There is no other way to say it. You can shop around on the Classifieds for a new set of keycaps. If you have to spend $100 on a new set, then do it. That $100 might sound expensive, but it's much cheaper than the $500 or $1,000 you're going to spend chasing your custom dreams. Start off easy, is my advice. Also, IMO MX reds feel really great with POM keycaps. You can probably find a set of POM keycaps with German legends for under $50. Something about the slick POM feel and the MX reds really goes together great. In fact it's the best combination of feels that I can think of, in the keyboard realm.