In terms of the swingarm, you could always purchase 2 used stock swing arms (ebay, etc.) and have them chopped and welded together with reinforcing plates to make an extended swinger.
You can get two used swingarms for around $150 plus the cost of fabrication and reinforcing plates. It's probably still much less expensive than some brand new extended swing arms.
This method allows you to use all the same mounting points for the stock swingarm skid plates, brake caliper, rear suspension, etc. It allows the use of the same carrier and axle. It will also maintain the stock look if that's something you care about.
__________________ 1989 Suzuki LT500R QuadZilla (a.k.a. SnowZilla)
** Camoplast (AD Boivin) Traxion+ Tracks ** Ski-Doo Precision Skis ** Engine Rebuilt and Bored Out ** Q Pipe on the way! ** V-Force 2 Reeds ** Graydon Proline Skid Plates ** DuraBlue Axle 1987 Suzuki LT500R QuadZilla (a.k.a. SnowZilla II)
** Virgin Engine ** Trinity Pipe ** Boyesen Reeds ** Ohlins Front Shocks ** LoneStar Steering Stem ** ProTaper Bars ** DG Nerf Bars ** PRM Bumper & Skid Plates SnowZilla on YouTube |