If you don't mind doing a bit of grunt work and if you are only doing it once the you could just open all the tables and do Table -> Append Rows to Table. This will give you a dialog asking which table you want to append to what, so just choose one of the states to append everything to and go through appending each one, one at a time, to this 'master' table. To make this a bit quicker and easier I would suggest following these steps;
1) Open all your individual layers (You can open them in 'No View' to keep everything a bit tidier) and make sure you have nothing else open.
2) Go to Table -> Append Rows to Table
3) (This step will save you loads of time) Make sure you leave the 'To Table' as whatever the default one is. This means that everytime you open this dialog you won't have to choose a different 'To Table', you'll just have to change the 'Append Table'
4) Change the Append table to the first one in the list that isn't the same one as in the 'To Table'!
5) Repeat from step 2, changing the 'Append Table' drop down to the next one.
Once you've done all this, whatever your 'To Table' was will contain everything, and you can then save a copy of this as 'All' or something similar.
I'm sure there is a better way, especially if you learn a bit of MapBasic, but if you want a quick and dirty solution then this should work. It's what I do whenever I have a couple of tables to combine that have the same structure. Addmittedly I've never done 48 tables so this might be a touch too much grunt work.
I swear I wrote a little MapBasic tool to do just this, but I can't for the life of me find it. If I do I'll update my answer, if not there are a few MapBasic gurus buzzing around here that will probably be able to put together an easy script.
EDIT: I did find the tool, it wasn't one I made, it was one I downloaded called 'COMB_TAB.mbx', but I can't find it anywhere on the internets and I can't upload it since I am at work and everythings blocked! There is another tool out there, but I haven't tried it, might be worth a go. - http://mapinfotools.com/index.php?option=com_sobi2&sobi2Task=sobi2Details&catid=8&sobi2Id=34&Itemid=53
There is also this Google Groups discussion that talks about an 'appender.mbx' tool that might be hanging around as part of your MapInfo install, but again, I couldn't find it