Feral orks? Wonderful!
I too am a fan of beast armies, (working on a beast heavy Kroot mercs army atm) and there simply are not enough of them in 40K. Nids are the only one to speak of (though demons are close) and they are too alien to be beasty imo.
Your boyz show a great start, and the war paint is nice, but I think they need more elements that emphaize their feral nature. I would suggest adding lots of bits from the kroot sprues - skin bags with bones, satchels, meat hooks etc... as well as trying to incorporate as many of the WFB savage orc models as possible. This would really help to bring out the primitive and savage flavour of your army. Heck, you could even use the boar boyz as bikers (like the old Cyboars...) with a bit of converting to bring them into the 41st milennium (albeit a pretty backward part of it
As for the gliders, I think it is a fantastic idea, but like Kauyon'la I think that they need to look a little more primitive. Perhaps using use little sticks tied together with string and bits of stiff canvas fabric instead of plasticard? I also am not a fan of the idea of adding rockets, instead I would have the pilot drop bomb squigs! He could have one caught in a net (easy to make from plastic or wire mesh, or string) dangling one of the struts.
And for the giant squigs and squiggoths, I have done a fair bit of looking around for alternative beasts for my Kroot, and I just stumbled on the company Scotia Grendel:http://www.scotiagrendel.com/page3.html
I don't know what policies you and your friends have about using non-GW minis, but they have some hilarious and wonderful beasts that would be perfect for all sorts of orky projects. Their prices are really good too, the smaller cavalry are about 7 or 8 pounds for packs of 3, and the largest warbeasts are in the 20-25 pound range, pretty fair when compared with the forgeworld squiggoths... don't know about their postage though...
Here is a taste of their crazy beasts:
Orc Gorathosaur with two crew
Black Orc Warbeasts
Lesser Goblin Wartower
Necrosaur with Harpoon
Titanosaur with Catapult
Titanosaur with Howdah
For ordering info, prices and ranges check out either http://www.scotiagrendel.com/grendel_creatures_1.html
and this guy has a blog that review some of the kits and had nice pics of some of his models and conversions (this is where the painted ones are from)http://leviathanwar.blogspot.com/2009_06_01_archive.html
I'm even thinking of getting some of the gorathosaurs for my Kroot... not as good a fit as for orcs, but it could work perhaps