Yes, there is a work around. Install SummerBoard 2.11 though Installer and it will list it as installed. Then perform the manual install to "activate" SummerBoard. You will then be able to install all the SummerBoard themes that are listed on Installer.
I have NOT done this, but have read a few posts where others have! Proceed at your own risk - SummerBoard is listed as an
Alpha version for a reason
Re: low space - the 1.1.1 firmware takes up more space so now there is less available for Installer app to use.