Size in email even if display variant is not on?

Is it possible to get the size into the email even if the display option of "append variant to product name" is turned off?

You should keep that option on and add CSS to hide it on your product page, like that:
.hikashop_product_page .hikashop_product_variant_subname{ display:none;}

Awesome, thanks, but these display like this:

Product Name: Small Black

I see using Firebug that "Small Black" is in a DIV, but the ":" is with the Product Name. Is there any way to make that colon go away?

If you update HikaShop to 1.5.5 by downloading it from our website and installing it, the colon will be in the span with the variants.
Otherwise, you can edit the file administrator/components/com_hikashop/classes/product.php (near the end).