You don't need a 3500. Just look at some of the newer lighter 5'ers. New technology has brought about a new lighter 5'er that's just as nice as the old heavy ones of the past. I tend to use the trucks RAWR when dealing with pin weights. If the pin is 1800 dry it won't be 3000lbs loaded. 3000lbs would be for a 15,000lb 5'er. Most 5'ers are balanced well enough to get you close to 20% of your loaded weight on the pin. Look for a 5'er with a pin that's close to or a little lower than 20% of the 5'ers UVW. That way when you load up you'll be close to 20% on the pin. An 11,000 5'er should have a pin around 2200lbs.
If you know from previous trailering how much you load into your trailers then you could simply add that to the new 5'ers weight sticker that's usually found on the door. Figure 20% for pin and go from there. I never use the 5'ers GVW as a gage for pin weight since GVW's and UVW's are not consistent. Some 5'ers have really high CCC and some really low. Mine has a 4315lb CCC. I don't even have enough storage to put 4315lbs of stuff in there. It has a GVW of 11,500. But I'm actually at 9000lbs loaded. By using the GVW for figuring pin I'd be at 2300lbs. 500lbs more than it really is.
IMO if you are putting 500lbs in the truck and have a 2200lbs pin you'll be at 2700lbs for payload. That's only 275lbs over the trucks GVW. I've been running 200lbs over for the last year. My 2500 CTD, except for rear springs is no different than a 3500. I'm certain yours is the same way. You will still be under your RAWR by 500-600lbs.