have a Swarovski AT 80 spotting scope with a 20-60X eye piece. The Cabela's spotting scope carring bag is not large enough with the eye piece attached.
Suggestions?

It hard to answer your question without more detail about your use. Creedmoor makes a very nice stayon case with carrying handles for around 35 bucks. I have a pelican hard case model 1600 with the pick an pluck interior which allows extra room for a cleaning kit, windowmount and extra lens. It easy to pick out the 1/2" squares to form the shape you want for compartments but it cost around 150.00 but you can drop this case with your scope in it and not worry about anything, total protection and waterproof with a lifetime warranty.

The soft cloth/fabric cases don't offer much protection if dropped and I use PVC pipe with threaded caps on each end, attach handle of whatever type you like, foam on inside for protection from bumps and it is waterproof to boot. You can get thin or heavy walled pipe and paint to suit and scope is well protected.
Just a suggestion.

Have the same spotting scope and use a pelican case. Protects the scope and keeps scope plus accessories all together.

I got my case at Harbor Freight. http://www.harborfreight.com/1...inum-case-39196.html

The back panel where the tools are hanging is removable and the dividers are also not put in when you buy it. It is pick and pluck 1/2" foam squares that you can make any shape you want.

With a 20% off coupon from many of the gun/outdoor magizines NRA magizine it will cost you about $20.00.

I have a Vortex Razor Spotting scope that I put in one. I do however remove the eyepiece when it is in the case. It would have been a real tight fit.