I definitely like the way the Hagstrom 8 string sounded on the "Axis Bold as Love" album. I don't know how practical it would be to have something like that, though.
I had a Hag 8 String from 1970 until about 5 years ago. It was a beautiful and unique instrument, but like you mentioned, not real practical, so I gave it up
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The hollow body Concord is a pretty nice bass but they also had a couple solid bodies in the late 60s-early 70s that were my favorites and they were cheap too. I can't recall the names, I have an old catalog around here somewhere that came with my 8 String that I have to find. There was a great sounding solid body that I saw Greg Lake use a few times that had a list price of something like $185. I played one at a couple of jam sessions back in the day and REALLY liked it. It seems like all anyone remembers from Hagstrom are their cartoonlike X Boxish creations. They really did make some other stuff that was really nice.
Rick