The least expensive alternative is to look for a used Roland MT-300 or
MT-300S(S=with speakers). Both are discontinued, but have a floppy drive,and
have built-in SoundCanvas sounds.
Another choice is the Roland MC-80EX which
has the Roland Sound board expansion, but
this is much more expensive since it is Roland's flagship sequencer.
There are also arranger modules such as the discontinued Roland RA-800 (has floppy). Also,I believe General Music still makes the "WK2 arranger module" that has floppy and optional hard drive. Korg also used to
make the i40 arranger module(floppy).
Hope this helps.