It is now officially released so please upgrade to 2.3.5

As for the out of stock button, it should be possible to change color by CSS (using ideas similar to those here: http://dukapress.org/blog/2011/03/18/replacing-add-to-cart-with-out-of-stock/ )

Something like this should work:

.dpsc_submit_button:disabled{
background-color:#999999!important;
}

Where #999999 is your color code.

Specifically:

It should work! Thanks for being persistent at this, it led to the discovery of a tiny, tiny bug that was preventing this (just changing one line of php).

Line 210 of dp-products.php should be:
if ($dp_shopping_cart_settings[‘dp_shop_inventory_soldout’] === ‘yes’ && $all_custom_fields[‘currently_in_stock’][0] < 1) { Unfortunately it is a small bug and if you want to wait for the *offical release to fix, it may take a little while. If you are not comfy with changing the code, please get the file from here: http://plugins.svn.wordpress.org/dukapress/trunk/php/

May I see the site please?

Hmm, the problem is that your theme is made in a way that it overides what were trying to do

I think skin.css line 257

Please try and use this instead:

.dpsc_submit_button:disabled {
background-color: #345!important;
background: none!important;
}

Please tell me if this works?