Larger AM frame for technical climbs. wife has approved the funding.

I have a Banshee Rune V2 which I am pretty happy with, rides very nice, rigid, handles the rough nicely and is pretty playful mountain bicycle . The main problem I am having with it and with most bikes is I have longer femurs than you, unless your 7ft tall, but my upper body is a more in proportion to the rest of me. So obviously my seat poles are typically at max height. Recently I have been playing around with some technical climbing and as soon as it gets step the front wheel lifts and off the back I go or lean forward to keep it down and I lose all momentum. I am skilled at this type of riding, but the bike I think is making it hard... specifically my seated position is pretty far back over the rear wheel.
The rune climbs pretty good for an agressive AM bike, as long as you sit and spin, great traction very little feedback, not as good as a DW link, but pretty close - trade off it is quite a bit more playful on the way down. So with pole at full extension, my arse is pretty much above the mid way of the stays. Things I could do but won't work are sliding the seat more forward = not enough room too cramped for handling. Longer stem would obviously get the centre of mass more forward, but at the detriment of the bikes excellent handling - 65mm stem is as long as I will go. Now when it's fast with a single tall obsticle to get over, I can plow through that without slowing, but when faced with multiple square edged hits so the bike is on a sustained angle things go to shit - the following pick is at a 10 degree ascent.
So at the piont my arse is only a fraction in front of the rear axle, the front lifts and the climb is over and I go home feeling inadequate. Now I am happy with the bike, it is a large and I think an XL would solve this to a point. A longer front triangle would help weight the front better in climbs, I can run the seat more forward in the clamp. The XL doesn't have longer chain stays, which would obviously help climbing - at the detriment of playfulness, but the wheel base is a little longer. So I am more than happy to buy an extra large rune to replace the large, I think my rationale is pretty good that an XL will climb a little better - or am I missing the obvious? My Mrs Flux at the same angle for reference, this bike climbs anything!
You do know this is a Portuguese forum,right?It's more XC oriented and you posted on the GPS section. :)
Given the post extention in the picture I'm sure your take on XL frame is right. To make things a little worst the Rune seems to have a pretty slack seat post angle (72º?)wich will "send" your saddle pretty far back with that kind of extension, I'm riding a big travel hardtail at 140mm (On One 456) that supossedly is even slacker (71,5º) but can climb anything other people in my usual group do with XC bikes. A saddle with a big nose can defenitly help in that area, not all sadlles are confortable to ride on the nose (for those really steep climbs).Have you ever tried one like the SMP's?Probably less expensive than changing frames, and the large nose area can make a really big diference in climbing.