I'm not sure how many native Spanish speakers are in the forum but translation of the template (.tpl) files isn't difficult. It would probably take 1hr or so...if you have the time.... :-) Just in case someone wants to know...Here's how...

1. Open a  admin/xxx.tpl file and find the hard coded text..For example...
<td> Thank You. </td>

2. Open _include/translations.ini and create an entry for gracias. For example...(in this case I created th GROUP [admin] but any group already in the .ini file is fine....such as [header] is fine but it's easier later to keep entries in specific groups.

[admin]
thank_you = "Gracias"

3. Go back to the open .tpl file and replace the hard text with the translated text. In this case....
<td> Thank You. </td>
becomes
<td>{$translations.admin.thank_you}</td>

NOTE:
1) no spaces allowed in translations.ini. Use  underbar between_words
2) Must use the EXACT format {$translations.GROUP.ITEM}