Do you think an 8m Peter Lynn arc (like a Venom) would be a good kite for landboarding? My concern is that arc's don't typically have good bottom end and fly pretty slow in light winds so I might not be able to sine it enough. I'll be kiting on hard packed sand in 8 to 25 mph winds. Or would I be better off with an open cell bridled kite (what I'm using now)?

Well you left out an important fact of weight and experience.
I use a 16M Scorpion in those winds, 25 mph is on the edge but 8 to 20 is great. the Scorpion turns very nicely and it's lift and float are sweet. Auto zenith is a great factor with Pl's, don't have to set them down to get pounded to hell with sand etc. IMHO

I weigh 245 lbs and flew PL's for 6 years. I've got 9 years experience on water and just started landboarding last winter. The beach here is long and narrow so we pretty much can only landboard when the wind is directly on shore. The fixed bridle foil I'm using is a 9 year old Airush trainer (the one I bought to teach my wife and a couple dozen other people how to kite). It sits real deep in the window and turns real fast, so I can generate power with it by sining, but it sucks for trying to get upwind at all. I've been looking for an inexpensive depowerable bridled foil (around 5m in size) but am thinking that an 8m Arc might have about the same power. Only thing is, I'm wondering how well it would fly in winds under 15 mph?

i fly in 8-10 mph with V13 all the time .(ATB) the smaller V10 i have works but light wind is ALL flying. the V13 seems perfect in the middle with power and turning speed...

for under 15mph anything smaller than a 13m would disappoint you, plus it has a lot range for a bigger guy

An 8m Twinskin won't do the trick in those light winds, but neither will an open cell dep-foil that small.
under 15mph a foil will fly before a twinskin will, but under 5m you won't really get enough power out of it.
I guess its a matter of what you want to do with the board, if its cruising along, why depower?
A "normal" foil is much more efficient, especially upwind.
If its freestyle you'll need a bigger kite.
Like Wolfwolfee said, in such low winds, between 10 and 20mph I'll use a 15m twinskin (and I weigh about 140)
Those Best kites 'll work too, it's almost a full quiver you got there, there must be one you can use in those circumstances.

Thanks, good points mj. I only "cruise" anyways, so I guess there's no big advantage to having a depowerable.