I've tried the 'x' style sharpeners in the past and I genuinely don't like them...I think every maker of one sets the angle slightly differently to protect brand loyalty or something. I had a Smith's 2 in 1 and tossed in the dumpster the second it couldn't put enough of an edge on an old SAK to slice through copy paper without ripping it

The only excpetion is the carbide draw through. I save that for VERY rare, emergency situations as any edge is better than no edge and it works fast.

Lee Valley Tools sells a kit like what you're looking to build. Comes with 2 ceramic rods, a guard rod and plans to cut and drill the block. It's cheap too.

I've also toyed with the idea of packing my Smith's 3 in 1 system. It's similar to the Sharpmaker, has lots of options and it's fairly light and small. Unfortunately for field sharpening it requires you to have a flat, stable base...something you don't always have, and again you're locked into the angles they provide for you accurate or not. The rods are pretty short in the Smith's so I'm going to try stashing one in the pen pocket when I get home and see if it fits. I'm not sure of the grid but it's finer than the 750 grit diamond bench style stone in the same device...so definately finer than the diamond steel rod.

I keep my knives pretty ding dang sharp so field sharpening is usually only needed if I'm doing a LOT of knife work or I make a mistake and metal hits metal or stone. That's also the reason I'd like to be able to put a proper edge on if I want to. I've tested the diamond stick sharpener and it's a good tool but the edge it leaves is almost serrated...no good for the push cutting you tend to do in the bush though I'm sure it would be fine for skinning and the like. Plus a fine rod can be double used for edge alignment like a steel without taking off much material.