Goldwings make great tugs. I have owned two GL1100s... and I wouldn't rule out a 1200 either, but they're heavier. Nice to have shaft final drive too. There is a reason they've been a popular choice over the years for a tug. The Yamaha Venture isn't a bad choice as a tug either. This is maybe a bit heavier than you're looking for, but are good (no, great) choices nonetheless.
Spending my daughter's inheritance one motorcycle at a time.
Bikes currently owned: '91 Honda Gold Wing with sidecar, '92 Kawi KLR650 with Enduro sidecar, and '94 & '97 KLR650s.