The roadster has a couple inches more ground clearance (can be leaned over farther without scraping the pegs).

 

True, but the maximum lean angle between the Sportster models is not as great as many believe.

Here are a few of the "lean angles" from the Harley site...

883 Lean Angle - Left 32* Right 32*
1200R Lean Angle - Left 32* Right 32*
1200L Lean Angle - Left 30* Right 31*
1200C Lean Angle - Left 31* Right 29*

As you can see, the angles are not that different, especially when you consider that the 1200R is 5 or so inches "taller" than the other models.

I think the main goal of the 1200R was to provide a model with a higher riding and seating height.

 

Also, in case anyone is interested, here is something I posted last year dealing with the 'seat height' of various 2006 Harley models.

Normally a Lower Seat Height means a Lower Center Of Gravity....

((In Order Of Lowest To Highest Seat Heights))

24.5" Softail Deluxe FLSTN/I
24.9" Springer Softail FLXSTS/I
25.2" Dyna Low Rider FXDLI
25.2" Softail Standard FXST/I
25.4" Fat Boy FLSTF/I
25.5" Heritage Softail Classic FLSTC/I
25.5" Heritage Softail FLST/I
25.8" Dyna Street Bob FXDBI
25.9" Softail Springer Classic FLSTSC/I
26.0" Night Train FXSTB/I
26.0" Softail Deuce FXSTD/I
26.0" Sportster XL883L
26.0" V-Rod VRSCA
26.0" VRSCD Night Rod
26.1" Road King Custom FLHRS/I
26.3" Sportster XL883C/XL1200C
26.3" Street Glide FLHX/I
26.6" Dyna Super Glide FXDI
26.8" Dyan 35th Anniversity Super Glide FXDI35
26.8" Dyna Super Glide Custom FXDCI
26.9" Road Glide FLTRI
26.9" Road King Classic FLHRCI
27.3" Electra Glide Classic FLHTC/I
27.3" Electra Glide Standard FLHT/I
27.3" Road King FLHR/I
27.3" Sportster XL883
27.3" Ultra Classic Electra Glide FLHTCUI
27.5" Dyna Wide Glide FXDWGI
28.1" Sportster XL883R/XL1200R
30.0" VRSCR Street Rod