Slippery, I finally took some measurements of the lift plates and sent them to you.
Ok, confirmed that Direct Lifts makes a bridge jack that fits my lift. It's the Pro Jack 3500, it's rated for 3500lbs and it's hand operated. Basically its a self contained hydraulic jack, it's just not air assisted like the more expensive BendPak's etc.
It's adjustable for width and sits on the main decks and "rolls" on nylon blocks. So it's going to take a little muscle to move it around since it weighs ~325lbs. However its the only option that fits my lift and is more affordable vs the other options.
Apparently it only sits 1.5" above the level of the decks if you don't have the "feet" on the jack pads. I measured my M3 and I have ~5" of clearance from the ground to the bottom of my front splitter, so I should be fine there. Just need to get the car back from the shop now. And get them to refund me as they charged me a totally unreasonable amount in labor for the work they did. That's another story that I posted in my build thread.
If I can gain a little vertical clearance by spacing the lift up 4-5", then I think I'll be in good shape. Race Ramps makes some nice ramps that I'll buy regardless, as the ramps that came with the lift are steel and weigh a ton. Moving them into place and back into storage is a real PITA.