I have a 27 DFWP as well. I have wrestled with how to secure not only street bikes but also dirt bikes and ATVs.
We have 2 Harleys that we haul and also (but not at the same time) 2 kids quads, a kids dirt bike, an adult atv, and an adult dirt bike. I was going to have some removeable wheel chock mounted but I could not figure out how to secure the removeable hardware to the floor without cutting the black membrane under the trailer so I could put a plate on the underside.
I researched and decided on this - http://www.boltiton.com/
- it is a little pricy but I figure that I can easily remove it when I sell the trailer. And by the time I bought a couple of removable wheel chocks and had the dealer install the hardware (due to the fact that I didn't want to be accountable for cutting that black membrane), I figure I came out ahead.
It hooks to the tiedown points that are already in the floor. Somewhere I have some pics, but it works nice. The bar includes tie down points and I ordered another chock for the 2nd Harley.
The owner is a super nice guy and if you call him direct and order and tell him that you want the same deal he gave me, you just might walk away with a nice discount!!
Let me know if you have any questions...