Wow, I made a big post and then lost it. Take two.

I've put up a 12m Spiderbeam pole + wire + base matching networks fed
against 27 ground radials ranging from 20 to 40 feet long. I'm using
it only on 80m, 60m, 40m, and 30m, and I've been quite happy with it.
As Cecil mentioned, it should work quite on 20m as well, but on 17m
and up it will have a less than desireable radiation pattern.

I'd still recommend getting the pole and autotuner. I think the
overall efficiency will be more related to what you can get in as
ground radials than which antenna you use. I think that the cost is
probably about the same in both cases. What you get with the 40 foot
pole and autotuner approach is a 40 foot pole and an autotuner! Better
parts to try out different antennas.

As far as the bands above 17m, two suggestions come to mind.

1) For routine, easy copy communication on 17m and up, just use the
antenna as is. It's bad for low angle radiation, but you're not going
to notice the differerence when you're hearing s9 signals that could be
s9+10dB instead. If good DX that you're having trouble hearing comes
on 17m or above, go out, drop the pole a few sections, and reattach the
wire to the tuner. Voila, your too-long vertical isn't anymore.
Cecil's suggestion to use a 21 foot vertical instead is just fine, but
you lose 80m in that case, and at this point in the sunspot cycle, I'd
personally take inconvenient operation on 17 over giving up 80m.

2) An old approach using new parts, if you can run a couple of wires
out at angles from the top of the pole. Put up an inverted-vee doublet
at the top of the 40 foot pole. Make some open-wire line to feed it.
On the lower bands, feed both feedline conductors against a good radial
system. On the higher bands, feed the doublet as a doublet. I haven't
tried this due to the lack of an autotuner, but I think it could work
quite well. It doesn't exactly fit your criterion of one 40 to 45 foot
vertical, but the visual impact is the same... maybe you've got some
trees or could tie things off to the house ... it's a top loaded
vertical on the lower bands, and a nice, high inverted vee on the
higher bands.

In the middle region, probably 30m and 40m, you could pick whether you
were using the doublet or the vertical depending on who you were trying
to contact.

73,
Dan
www.n3ox.net