Possibly. Like I said, I don't know for certain if there's an upper limit or not in terms of proton number, which determines the element in question - but bear in mind, they contain charge, which complicates binding them in a nucleus - then again, neutrons help bind them together.
Neutron number is limitless, as they don't carry charge, however, if proton number stays the same, then you're not creating new elements, only isotopes (e.g U-235 and U-238).
Something I just found online if you're interested, a rather nice graph, a nuclide chart:
http://www.nndc.bnl.gov/chart/
This plots a point for every known combination of mass number (x-axis) and atomic number (y-axis), and colours the point depending on the lifetime of the element created. There does appear to be a tailing off so perhaps one day we can truly say there's a complete Periodic table, but maybe we just haven't filled in all the dots on our graph yet...
Again, apologies if this isn't what you're looking for....