Yes, but you'll have to do some dependency digging. The actual conversion of an RPM to a DEB is fairly simple.
Download the RPM. In this case I found it here (takes a while to load for obvious reasons).
fakeroot alien rosa-launcher-0.34.5-1.1-mdv2011.0.i586.rpm
Now you can install it. Whether it works or not is up to you having the right dependencies installed and it being compatible with a different version of KDE. You can see the core dependencies here but remember these are Mandriva packages - their Ubuntu equivalents might have a different name.
You might just be easier downloading the source for the package and compiling it under Ubuntu but that's going to require finding out even more dependencies and then learning how to compile one of these things.