I see what you mean.
You want to make it state of the art.

So that will track also the moments that some ppl logs into it's alt, or has a fast disconnect.
In my opinion would be good enough to be able to track ppl online not for giving them dkp, just to give them hourly points, other then dkp, you can call them how you want, so that i can see in future who is more online in the raid hours then others.
A feature that can save a variable for everyone in guild, in/out of raid, that can also track atls, and can store the number of hours a player is online, or just to give him one point per hour, would be good enough for me.
I tryed to add this feature into the dkp system as I didn't imagine that no DKP system can track entire guild, or can give by one click an amount of DKP to a filtered list of players inside the whole guild.
I set up the dkp so that will matter attendence hours, but seems like I don't have the suport for it.
A feature to sort the list of the guildies, and cut out offline ppl, and give DKP or attendence points hourly by one click or by a popup window that pops up hourly (or the amount of time i set it), would be really nice.
Other idea would be to have a button that will check everyone online and level=70 in guild, and assign to main character of the online person, a point for attendence or a dkp amount would be great.