What timing you have!
I've just purchased a trailer that was previously situated under a Ranger 29, and snapped up a ton of photos of it empty.
LINK
I need to modify mine to fit another boat, but I believe several folks here use this trailer under their Rangers. It's a FloatOn Pioneer aluminum, triple axle. Trailer weight is 1,820 lbs., GVWR is 15,240, net capacity is 13,420.
I've not picked up the trailer yet, won't have it in hand for another week or so. Once I have it back home, I can get you any measurements you wish.
I'm also curious to know if an R29 would rest on it's keel on the trailer above - as that's how I'll need to configure the trailer for my incoming boat. Does anyone here know if the keel of an R29 would simply ride on the yellow plastic pieces shown on all the cross members in the pics above, or would the hull be completely supported by the bunks?
Prior to purchasing this one, I also called a couple of King trailer dealers down here in WA. My guess is, given their proximity to Ranger they've also fit trailers to the R29 - and I was quoted about $9,400 for one of their triples with similar capacity. Didn't get the details on the brakes they offer, though.