Hi,
new added themes can not be found in the new theme-garden, you allways see the older submissions.
Why submit a theme in the theme-garden, when no User can find it, the only benefit is the installer.
Themes you host on dropbox,
box.net, gdrive ... can easy deleted or updated....
and premium themes can selled via
sellfy.com or
sellboxhq.com without giving 50% fee to any other Website, the fee is here 5 or 9 %..
Tumblsphere is only a showcase, to put them together, it does not matter if your theme is in the themegarden, on dropbox or elsewhere.
Thre is an older post about this: