I actually replaced mine with WASD keys here are my notes on it.
The F key row is an R5, good luck finding them.
Using an R4 works just fine, but leaves you with two ways to solve a problem, neither is perfect. The problem is that the Escape and Delete key will be a 1x instead of 1.5, good luck finding R4 1.5's. You can either use an R1 1.25 or and R4 1x. The r4 will maintain row height (but not increase like stock does), and will still leave you with a gap between the keys (but smaller), I went this route as I bought the board partly for the circuit board. I liked the looks of it, so exposing it for me isn't an issue. Your other option is to use R1 1.25 keys, this will give you nearly full width, but the keys will be a bit lower and an odd profile. I use an R3 key for my FN key so I don't accidentally hit it when I hit the backspace, but I considered getting an entire row 5 made of R3 keys for the same reason. I seem to need a small gap between my numbers and f keys. WASD does happen to sell R3 1.5's, these tend to be the flatest profile caps on the board as well as the lowest in height, and a full set labeled, would get expensive. If you were to do a full set, you could use some of the numpad and other modifiers to reduce the cost (you could get 6 out of those), but it would still add up fast if you labeled them.
After that, you need a different page up, page down and end key, all of which are simple.
Arrow keys you have two options. Order a set of 4 R1 1.25's (I recommend blanks to make it cheaper) or just go with standard 1x keys (what I ended up doing).
If you order from WASD, and you do the custom keyboard layout and tweak it, you can make a full set, with legends, like I mentioned above, for about $68. I have the pattern if you want it (even has the modifiers), but the font is one size smaller than normal.
Here is my post with the results, as well as a link to the pattern (I corrected the D key).
http://geekhack.org/index.php?topic=39116.msg765881#msg765881It's not perfect, but to me it looks fine all things considered, though the PBT's Vortex is sending will probably replace them.
Otherwise, you can try and get ahold of Vortex and get a complete set. They have ABS and PBT, my recommendation is do NOT get the white ABS, and good luck. User
Vortex-JC is a Vortex representative. How much good it will do you, I have no idea, but send them a PM and cross your fingers and you may be able to work a deal for some OEM caps. You might have better luck using their Facebook page, I don't use it and really wish companies would get over it and realize it's not a real website or technical support site, nor is it a replacement for it. Websites are cheap and there is no excuse for not having one these days if you make anything.