lagers need pretty substantial amounts of yeast. mr malty is good but you can use other resources to engineer a smaller starter with the same amount of necessary yeast. you could use 2 yeast packs in 2 gallons and that would work. 4 yeast packs in 0.8 gallons also works. Using a stir plate you could use 2 yeast packs in 0.75 gallon starter and that would also work. another thing to consider is if you refrigerate your starter for two days and decant, you will reduce the liquid you dump in your wort while still managing to dump in most of the yeast.
'Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne.'
—Kurt Vonnegut, Breakfast of Champions