Beeks, you're so sweet *hug*. I appreciate the thought, but I've tried several types of Ludwigia, and just didn't find it suited the tank. I'm actually leaning towards something that's a) not a stem and b) a completely different shape than anything else in the tank - if the Lotus doesn't work, or I can't find one, I may try something else that meets those criteria (or do nothing for now).
Mooch, it was rediculously high maintenance (full of stems, my choice), and was going from nicely full to jungle within a matter of days, requiring weekly or twice weekly pruning. I'm starting to experiment now, and the only two really fast growers left in this tank are the Hygro and the Rotala (which grows much slower than the Hygro). Things like Bacopa are easy to keep in check compared with H. polysperma - you can almost watch Hygro grow before your eyes!
I'd love to see your tank, I'm becoming a real Crypt fan and it sounds very interesting; having too many stems is losing its appeal after 5 months of snipping and replanting in more than one tank, I've started cutting back and need some background ideas for my 14g and maybe the 65g as well.