I want to right click on one or more files in Konqueror and create a new mail with the files as attachments. Is this possible?
Yes, by creating a service menu entry.
In the directory .kde/share/apps/konqueror/servicemenus, relative to your home directory, create a file called sendto.desktop with the following contents:
[Desktop Action SendToMailRcp]
Exec=kmail --attach %F