It's that time of year again!
This is as good a time as any to dust off this old thread on flying into Oshkosh.
http://www.vansairforce.com/community/showthread.php?t=8960
Not to pick on the OP, because this issue comes up every year, and for every person who posts a question, hundreds more are wondering the same thing. I recommend you start post #1 in the above thread, which is an excellent article written by Rick Durden after Oshkosh 2001. It was inspired by a fatal accident involving a Glasair on the Ripon/ Fisk arrival in 2001, and is very relevant to this question.
Gary hit it on the head. Every RV design can fly just fine at 90kts. If you are not up to the task, then you owe it to yourself and the rest of us to either get some additional training until you are proficient, or stay away from Oshkosh. This is a huge safety issue, and not the time to be nice or politically correct.
Some of you will, after careful consideration, still decide to try to sneak in on the high/ fast approach. You might get away with it, but consider this. I've heard many times in the past where controllers have ordered planes (like RVs) to depart the high approach and fly the low pattern. So you need to be prepared to do so, even if it is not your plan.
My first year flying my RV to Oshkosh (2004) I was behind a T-craft, with a Glasair behind me, so I can sympathize. The NOTAM is very clear about what to do when this happens, which is to break out of the pattern and re-enter at the beginning, and you need to be mentally prepared to do so. I highly recommend that you plan your flight to make a last fuel stop somewhere around 30 minutes from Oshkosh. There are plenty of airports in southern Wisconsin that fit the bill, and you are much better off to hit Ripon with full tanks and empty bladders, just in case you need to go around, hold at Rush Lake or taxi for 45 minutes after landing (sometimes all 3 in the same flight.)