A router plane doesn't really need
any gizmos, imo, the "old woman's tooth" (didn't old men have distorted teeth a coupleof centuries ago??) style does a perfectly adequate job & you can make one for yourself with a base or bases to suit your own needs.
Years & years ago I picked up a 71 at a garage sale for a pittance. I just could not get along with it. I know why now - the blade that came with it was in very poor shape & I lacked the skill & understanding to sharpen it properly. I ended up passing it on for the same pittance (which I regretted when their value skyrocketed!
).
A few years back Derek Cohen posted a
home-made version which intrigued me, so I whipped up a shameless copy (more or less) & discovered it was a
very handy little device, despite its raw simplicity (I'd learnt much about sharp edges in the interim!):
The pic was taken before I realised a depth collar was obligatory for repeat work, but that was easily attended to as an afterthought.
While a simple OWT may lack the refinements of its metal-bodied descendants, I can't think of anything they can do that mine can't. And given how infrequently they are needed in most routine cabinetry, I reckon mine is a better bang for the bucks....
Cheers,
Ian