Wondered if there was an aftermarket provider of a kit to retro fit rubber mounts to the earlier bikes. If there is, has anyone done this?

There is not that I know of. If there is it would be an expensive proposition. I think you would be better off just buying an 04 and going from there. But some people love challenges and that is certainly a good one.

Thx for the info. I suspected as much, but thought I'd ask. I didn't know if there were major differences in how the engine mounts were designed.
Actually, I don't find the vibration to be unreasonable.

I actually think that the reason behind there being no aftermarket rubber mounts has something to do with the engine helping to support the frame. At least that's what I read somewhere here on the site, unless I misunderstood what I read.

In pre-2004's, the engine is a "stressed member" of the frame, in other words, it helps to support and strengthen the frame. When Harley went to rubber mounting, they had to significantly enlarge the frame tubing, (which is where most of the extra 50-60 lbs. comes from) to compensate for losing the engine as a support. (I wonder why Harley didn't use counter balancers instead, like on the Softails? It would have only added a few lbs).

Never knew the engine helped support the frame, neat engineering, just horrible vibration, I need new grips and seat

I dis- agree with the frame being a "stressed member" on a rigid mount seeing how it's a full cradle frame that carries the weight evenly. Now if your talking a Buell or Ducati then yes those frames are stressed member frames cause you can slide the motor out from the top down.

Buell's geodesic perimeter frame utilizes triangulated sections, proven to provide maximum stiffness. The engine serves as a planar stressed member of the frame, further enhancing rigidity

Chassis 101: The solid mount XL frame does gain some rigidity by having the engine bolted into it a multiple points. Buell engines are rubber mounted and therefore contribute NO frame rigidity. Both frames worky pretty well.........then there's the '04 and later XL. Rubber mounts, humongous frame tubing and a flex-o-matic swingarm mount. OOPS.

Wondered if there was an aftermarket provider of a kit to retro fit rubber mounts to the earlier bikes. If there is, has anyone done this?

Buy a tuber Buell frame.
Ralph