I wanted to use an existing MySQL table and find that there are some table names in XRMS that clash with existing tables. Does anyone have any experience/ideas on creating table prefixes?
It has been done, and there are even some forum posts about it from several years ago, but it's really, really not recommended.
It's trivial to create a new database in MySQL, and xrms expects to have complete control of the database, so this is your best option.
And if you're using a cheapo web host that restricts how many databases you can run, you probably shouldn't be running an enterprise CRM system on it anyway, as that means that they are sharing one mysql daemon across multiple clients, and you should be seriously concerned about both performance and security of your data/apps.
This was purely for evaluation purposes and I want to keep this and the other apps it all in one place.
As Brian pointed out, prefixing the XRMS database tables is far from trivial. The system was not built that way and there are good reasons why such code structure would be of little value. Even if you are looking at integration between XRMS and other systems, merging the databases runs counter to good practice so I would, too, strongly recommend against going that way.
If you are just evaluating XRMS, the easiest is to just fire it up on a separate server/hosting account to do your evaluation. Going beyond that would be way too resource-intensive as a mere evaluation. On the other hand, if you have something else in mind that would justify the effort, it may be a good idea to give us a bit more information so we can hopefully comment on the best way to approach it.