I'm not an expert in this but I'll try answering otherwise this question will get stale.
It is possible to use frameworks other than JQuery Mobile and the help page at http://docs.rhomobile.com/rhodes-jquerymobile#modifying-a-rhodes-project-for-jquery-mobile explains how to do it.
Before Clicking please be aware the documentation page appears to be out of date, it is describing how to transition from JQTouch to JQueryMobile whereas now we ship with JQuery Mobile by default... nevertheless the process for transitioning from one styling framework to another should be identical.
I think it's not so straightforward, if you want to retain all features.
jqmobile-patch.js has a number of customizations to JQM for dealing with Wait pages, and other things. (Yes, I am being vague, whenever I look at this file I get an ill feeling and have to stop looking at it...)
How much of this is really necessary I don't know, nor whether this file is really uo-to-date for current JQM. I notice it's using the .page() funciton which is now deprecated.
I think the best thing is to search here and on the Google Group. There were some users a while back that started using jq.mobi, and so their experience might be useful.