Thanks, everyone, for your advice! I got two recommendations for Marcello and an e-mail from him, so I am strongly considering his 6-course Duiffopruchar: http://www.armandpilon.com/galleries/duiffo6.html
Another lute I really liked was the Descant by Larry Brown: http://lkbrownviolins.com/descant_lute.htm And the third, the most beautiful one: http://www.lucianofaria.com/Imagens/WendelioVenere1.jpg It is also the cheapest (perhaps because of the 44 cm string-length), and is a treble lute; I'm not sure what difference this makes. Anyway, does anyone have an opinion on which one I ought to choose? They are all fine lutes, I think. To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
