Reducing yeast starter volume by increasing gravity?

I have been making yeast starters for years, never really thinking too much about them...however, I just started playing around with the new BS2 Yeast Starter calculator...and realized that I may not be making my starters correctly (and under-pitching likely has caused some of the fermentation issues that have been plaguing me!).

I am currently preparing to make a fairly big beer OG:1.070, and BS2 is telling me I need around 3 liters of wort to propagate the correct amount of yeast for this batch (without stirplate, which it looks like I may end up investing in soon).

However, if I use the recommended starter gravity of around 1.038, and 3 liters of wort, this is a large enough volume of low-gravity starter, which I would think would significantly affect the gravity of the actual batch of beer...not to mention that I can't use my nice 2L flask anymore...so I am just wondering if using a starter with a higher original gravity could be factored in to the calculator to reduce the volume of starter needed? It seems to me that the issue is more related to the amount of sugar available for the quantity of yeast that you want to propagate to is more important than the volume of the starter itself...?

You can let the starter go untill the yeast flocculate and drop to the bottom then decant and pitch. But I wouldnt increase the gravity over 1040. You want to wake them up and grow yeast not make beer. At this point they need an aerobic environment so less sugar is better.

I made my stir plate with stuff I actually had lying around. I didnt spend a penny on it other than the stir bar.
~ An old hard drive, an old computer fan and some computer mounting hardware, an old power transformer and a pentometer from a broken guitar to turn it up and down. Some scrap lumber and I was set. I found a simple dyi on byo http://www.byo.com/stories/projects-and-equipment/article/indices/20-build-it-yourself/401-build-your-own-stir-plate and followed it to the T. Saved myself 60-100 bucks for about 1 hour work of work and an hour or so of scrounging parts. Good Luck!

Thanks for the info. I'm totally going to build a stir plate now, I too have most, if not all of that stuff at home or at work! Actually, I have access to some magnets that are downright dangerous...but fun...  ;D