Wayneburg--
The Velcro may be quieter in that it doesn't clink or jingle, but it will be a darn sight noiser when you open it (r-r-r-i-i-i-p-p-p); don't know how important that may be to you.
If you just want to add capacity, you can get a bigger ring, add a second (or third) ring (seems to be your choice), or do both. If you want the 'biner (or Velcro) as a quick-detach device, why not simply interlink the two (or more) keyrings? They will still separate readily, but be held securely. I've used Velcro in this manner, & was dissattisfied with it on a long-term basis. Short term, field expedient use was OK, though.
I use a fairly strong ball-detent key ring separator to attach my Photon to my keyring. Along with its 3 inch lanyard, it gives enough length to use to light a keyhole, while still attached. If I need to detach it, it's but a thumb-sqeeze to do so, & it reattaches quickly, too.
I second either the Photon II or the ARC AAA. Already have several Photons, & have an ARC AAA on order.
Look at the SeberTech line of tools. They're made to attach to a keyring--& detach quickly, too--no split rings needed. The basic is the M2; the top of the line (i.e., most tools/functions, & most "Leatherman-like") is the M4. The M3 is the best compromise. They can be had for under $20, I think. They make the ones marketed by Sears under the Craftsman label. I have an M4 in my miniature toolkit at the office.
Good luck. Let us know your choices.
David