We have some tables which we need to generate on the fly, and they are of different length based on the subscriber. Is it possible to import pre-rendered html into a template on a per-subscriber basis? Would we need to add the html as a field in the subscriber list, and then put it in the template?
You can store HTML within a custom field which you can use to display within the campaign. However, you need to be aware that all custom fields are limited to a maximum of 250 characters, so the HTML will need to be short.
Another alternative would be to consider using our Dynamic Content tags. You could then have a set number of predefined content blocks that will only display dependant on a specific value in a custom field etc. Full details available here: http://help.campaignmonitor.com/topic.aspx?t=535
That may well be a good compromise in displaying specific content to specific users of your campaigns.