Personally, I play a bit of lute music on six-string guitar. Adds a little sparkle compared to nylon strings and where a lot of lute music has open strings to give harp-like drones, these sound nicely like a brass-strung harp on guitar. Tuned EADF#BE, capo 3 gets you to lute tuning.
On 12 string? I would LOVE a unison-strung 12-string guitar, but I cannot get on with octave stringing on a 12 for anything other than chordal work, hence I prefer octave mandola to bouzouki.
Was the original question whether it's possible to play a lute like a guitar? That would give you a guitar which is playable at Ren faires. The answer is yes, however...
Standard 6-course lute tuning would be GCFADG, according to my book, and this could easily be retuned to GCFBbDG, i.e. standard guitar capo 3. You then just need to remember to modulate the key so if the song/tune is in G, you play the accompaniment in E and so on. Tuning down three semitones would give a sound like a shoebox with rubber bands on it, not enough tension.
There are also a number of travel guitars out there with odd-shaped bodies, some of which are not dissimilar to mediaeval instruments, which you could probably get away with from a distance. I've always fancied having a nylon-strung six-string made on a lute body for this purpose.
Hope this is what you wanted.