No, on peer you cannot change that. Use an OpenNap server instead, despite no multisource functionality, the search/browse results can reach a maximum of 65,535 but will be limited to the max configured on the server, which could be anywhere from 500 to 20,000 usually. Not all the OpenNap servers have the same browse and search limits, you would have to try them, some are set much higher than others.
A current list of OpenNap servers listed on GotNap can always be found on this link:
http://www.gotnap.com/index.php/listFor WinMX clients, you can download the .wsx file from this link:
http://www.gotnap.com/index.php/clientSave to desktop, then drag to your WinMX desktop icon and the servers will be imported. You can also choose to open the .wsx file with notepad to view the information and manually add into your WinMX client if you want to do it that way.
For anyone having just an issue with using WinMX on Windows 7, copy your old folder for WinMX to the root directory of C drive (C:\WinMX), and not in programs, and just click on the WinMX icon and it runs, there is no need to install it. Configure WinMX to always run as administrator, or your downloads will not save to disk. Right click-properties on winmx.exe or the icon to always run it as administrator without having to tell it each time.