[orca122]

+1 for above. I believe the current pricing of mag swingarms is based on availability as few were made. Carl Foggarty actually tried a double sided swingarm for weight savings and control of torsional rigidity but it didnt pan out.
Stock swingarms are easily available. I dont have an extra but could source one as listed. The cost of the new swingarm would be the limiting issue for me. Of course it would have to stand up to its intended use. A pretty and light but nonfuctional part is not gonna work here. I would be willing to track test a unit. Consinder the price of used 848 swingarm as a good price point comparason.
This may seem intuitive, but if some non bike oriented is woking on extending a stock swingarm on cad software, remember to stretch it outside the rim/tire diameter. The use of stock suspension connectors and bearings would be excellent as well.
Please do try to get a price estimate. Brad