There is no equivalent to the Time Intelligence functions if you want to create say, a moving range (difference between successive values), a moving average and so on. Your only choice is to "manufacture" a date field and use this field in your calculated measures. There are a few ways to create a date field - all require a sequence number field, with no gaps in the numbering.
1) If your table has a sequence ID or similar field with consecutive numbering, you can use this field.
2) If you have no field you can use and a) your table is not too large (<1M rows), b) you're using static data (i.e. the table doesn't need to be refreshed periodically, you can bring the table into Excel, create a sequence ID field and then link the table to PowerPivot.
In either case, it is best if your consecutive numbers start from 1. If that's not the case with an existing ID field, you can create a calculated field in PowerPivot that subtracts an offset.
Once your sequence ID field is ready, create a date calculated field (call this FakeDate, for example) using this formula:
=DATE(2010,[ID],1)
[ID] is the name of the ID field and represents the month. 2010 is the year (you can use any 4-digit number >=1900 for the year). 1 is simply the first day of the month. Month numbers that are greater than multiples of 12 roll the date over to the next year, so for example, DATE(2010,13,1) becomes 1/1/2011.
You can (and should) hide the fake date field from appearing in the PivotTable you create, but still use it in your calculated measures.