The Armor/Mod rank 23 and above do exist.
You buy the rank 23 from Mission Support Vendor for 8 daily tokens each (only armor/hilt/barrel, not mod) in either Belsavis or Illum. You get these tokens as reward for doing dailies.
If you do the 2-4m hc dailies there, you get 3 tokens AND depending on the quest a Mod/Enhancement/Armor rank 23.
I don't know if these can be RE'd to get the recipe for them, BUT I do know that the recipe requires an epic crafting mat that only drops from the high level hardmode FP's/Ops (I got one from False Emperor HM and Soa normal mode 8m)
So welcome to Cybertech 400, make your grenades and rides, then swap to biochem, get to 400, get the 5 reusable stims/adrenals/medpack (2/2/1) for your class, then go level something worthwhile that will make you money.
As it is, everything cybertechs can craft to make creds (APART from Ship upgrades rank 6) can be had better from a few daily tokens/quests.
The only notable exception are earpieces, but to get a worthwhile prefix for your earpiece (and not some useless +presence!!) when you get a schematic, you need to be lucky.
Still with that, you need to crit on the crafting and produce an earpiece with an augment slot for it to beat the 120 daily token earpiece (120 takes ~6 days if you make ALL dailies)
So yes, call me embittered - Cybertech was my first love - but now I'm biotech 400, sticking with it until I get 2 more Biometric crystals for my offspec stim/adrenal, then I'll do something else.
And yes, I can still use my grenades/BoP ride from cybertech while having biochem
And the biochem epic bop reusable consumables are also usable without biochem.
And to answer your RE question - everytime you RE an item, you have X% chance to learn the next higher schematic (prototype from green, artifact from prototype), so it doesn't matter if you RE 10 of the same items at once or one by one. If you do it one by one, you can stop crafting once you have the schematic instead of wasting mats on crafting the lower version.
(Note rank 24-25 mods are gotten by pulling them out of columni/rakata weapons *sigh*)