is it possible to create a grid in a saved search email?

I think so, using HTML tags like <table> etc, in the Customize Message subtab under Email in the Search configuration. I haven't done it before, though, so I don' know if it can handle ${freemarker} or if it expects {field_tags}, and if/how it knows which search result to put where. If it can handle freemarker, and knows to put the whole result set into each one email, then you can use #list to render each search result row.

@Aaron McCausland Alright, sounds promising! What list shall I for? Do you think you have more of a start of the code?

Well I tried a quick test, and it appears that the Saved Search email customize message feature doesn't actually support Freemarker like Email Templates do. So to make your own dynamic HTML for the emails you'll have to use a script or workflow and use the email templating features in one of those. BUT you may not have to do that, depending on what information you're trying to put in the grid. If all you want in the grid is the search results, with the column names as the table/grid headers, then the saved search email feature automatically does that for you if you tick the radio button for Summarized Results: Send within Message. It doesn't put border lines between the grid entries, but it does line them up on a grid layout that's essentially an HTML table. It just doesn't let you decide the style, or the layout beyond what you set up in the Results subtab of the saved search configuration.