It is what it is. You can always send two emails. Simple, if not elegant.
This is why many people have taken to storing their documents in the cloud. It's easier to send links than attachments. If you absolutely must send multiple attachments of different kinds in a single email, then you can use GoodReader. The down side is that you must copy all files to GoodReader first (excluding photos, which it can access directly)
For Pages, Box.net is an easier solution that DropBox. It's free account has WebDav access that will let you save your Pages documents directly from the app. GoodReader can be configured to access and download files from many cloud services; including DropBox and Box.net. So though it takes an extra step, it isn't particularly hard.
Yes, this is a pain to set up and do for a single email. But the point is that you don't do it for a single email. You do it for your entire workflow, and once it is set up, and you are used to storing your documents in the cloud by habit, it's quite easy to do.
The benefit is that your documents are suddenly not just on the iPad, but also on any computer that has internet and a web browser. It's not all roses and parades, but thats where the mobile world is heading. It should keep getting better and more convenient as time and competition do their usual thing.