Thanks for these suggestions.
I have found plans for a speaker that looks interesting. The following review really quite raves:http://6moons.com/audioreviews/zigmahornet/zigmahornet.html
Builder comments in several forums vary a lot: None rave, like the 6 moon review, others affirm the great imaging, but note the limitations with more emphasis than 6moons. Others are quite disappointed in the speaker, though it seems that at least several of the most disappointed builders didn't use the recommended driver, or took liberties with the design.
Taking your advice to heart, I really don't want to spend a lot of money on a kit or home-brew speaker. One of the virtues of this speaker is it is cheap and easy to build -- so I can try my hand at speaker building without risking money I might prefer, at the end, to have put into a commercially built model.
If this speaker fails to satisfy or falls short of blowing my Linn Index II's out of the water, well, I won't have spent a lot, and I will have tried. In that case, I'll be looking for good alternatives.
In that likely event, I thank you for directing me to the Tyler speaker. This looks to be a very interesting possibility.