I ended up locating a set of 1969 Z-28 "short" steering arms. Very happy with the purchase/ transaction, btw. (Coast 2 Coast Camaro) He shipped them the same day and they came cleaned and primered. I think they have more if anyone is looking for them. I got them here:
http://www.coast2camaro.com/parts.aspx?cid=16
They were the same price as the L&H aluminum ones, and these are forged steel. I feel a little safer with that.
Turns out my car had the mid length arms after all, which is what I thought they should have had...
Even with this it looks like I'll be using 18" rims and with some fender trimming I'll be in business. I'm estimating 18x10 in front and 18x12 in back with full steering/ suspension articulation.
Thanks again for everyone's help!