If you're going for portable use, you'll want stranded wire. Otherwise, CAT-5 cable is an excellent source for 8 strands of #22. But it's solid core.
I am a PBX Technician for a living. Your statements are partially true.
-Cat 5 cable these days is almost "unobtanium". The PLANET had eveolved to Cat 5e...at the MINIMUM. Cat 6 is the "latest thing".
-MOST LAN cable is 24 gauge copper. 22 wouldn't fit into most connectors.
-the solid conductor data cable IS used for the station drops, but stranded conductor is available as well. It's used for patch cords.
Other than those nit-picky things, they're still excellent ideas. I have 3000' of satin cord in my truck. That could be an excellent choice for counterpoise wires.