(Assuming a new RA logo is something the community really wants), I think we're starting to get too hung up on ways to modify the Rust logo to get a RA logo. Consider the Cargo logo: a bunch of cardboard boxes on a shipping pallet (arguably those boxes should have been crates?). The Rust logo is barely noticeable in the logo. The Cargo logo stands on its own, suggesting cargo, crates, shipping, manifests — all real things that that Cargo is/does.
I think the RA logo should go down the same path: taking some novel concept that describes what RA does without reference to Rust itself, and then figuring out where we can place the Rust logo in this design.
(All this assuming we want a new logo at all; I'm 50-50 on whether the current RA logo needs sprucing up. The r.a in a square looks pretty nice.)