Forms Data Controls :: GridView Alternative - Facilitating Data Input

I have been using Gridviews throughout a website I am currently building, however one particular requirement is to display two tables side-by-side that butt up against each other for the purposes of data entry. One person inputs numerous entries on the LH table whilst a different person will respond to one or more rows in any particular order (ie row 2 may addressed but row 1 might stay blank for a period of days). As far as I am aware, a GridView (or two) won't suit this requirement for the reason (from my still new understanding of GridViews) of not providing the ability for a 'respondee' to address any row in any particular order. Whilst I could add a button to each GriView row which displays a detailsView/FormView horizontally in line, I would still have to populate the Gridview with empty rows for those rows not addressed plus this 'fudging' just doesn't bode well concerning DB management.

It just seems adding two asp tables side by side then somehow working out how to automatically present a new row for data entry for the left hand table and creating a second table being the same size as the first (according to its number of rows) would be the way to go, then the task of data gathering/uploading to the DB. How best address the requirement - there maybe better ways for facilitating data input as opposed to using side-by-side controls, however it is the clients request. Also I don't want to go expelling copious amounts of time to fully customize a gridview when simply creating some sort of dynamic table would be sooo much quicker and easier for this once off. I have tried some searching, however not knowing where to start is problematic as 99% Google results return GridViews (as you would expect).