You're on the right track. A bench top planer will go down to 1/8" much better than a larger one will, due to the distance between the rollers. Mine is an 18" and although it will go down to 1/8" the thin pcs. vibrate ( because the roller are too far apart ) too much and too many of them will self destruct. I've done work at places where 1/2 the walls were radioused. And to make the trim, crown, etc. we built a carriage for a 12"er w/ in and out feed extentions. Used planed poplar to make a base, then the same to frame up in and out feed, with a opening in middle to set the planer in. Shim up even w/ in and out, bolt it down. We then resawed our stock to 5/32, a light pass on each side to get to 1/8". A couple tips on what we did--- 1- continous feed, in other words as 1 or 2 pcs. got halfway through, we started in 1 or 2 more, or on wide stock butt the next pc. to the one in front that way you only get a slight snipe on the first and last pc. ----2- before we resawed, we put registration marks on the end of the stock, so that even if we got something mixed up, we could glue them back together in the form in the same order that they were , that way after bending and glueing back, all the grain fitted together and it looked as though it was a solid pc.. Got just about 100% results using the carriage, and on some jobs we would resaw and plan 1000's b.f.
HTH
Roger