I can't do something like this (regarding the `or`)...

    if (not position.x == 0 and velocity == -1) or
            (not position.x == 500 and velocity == 1)

Nor this...

    if (not position.x == 0 and velocity == -1) or (
            not position.x == 500 and velocity == 1)

I have to do something like this...

    if (not position.x == 0 and velocity == -1) \
           or (not position.x == 500 and velocity == 1)

I would like to be able to do it the first way.

Actually, I can do it the second way.  I must have typo'd when testing (my apologies)...  But I'd still like to do it the first way. ☺

Sorry, I don't think this proposal has a chance.  

Python doesn't require statement terminators like ";" in C.  Accordingly, it needs to have a clean and consistent rule to close a statement.  The rule that has worked well for us it that a statement is terminated by a newline unless there is a line continuation character, or a colon to begin a new suite, or an open expression delimiter (parenthesis, square bracket or curly brace). 

Adding a special case exception to the rule might look nice but would complicate learning the language, and it would complicate the implementation as well.

Agreed that this isn't likely to change.

If you have a concrete proposal for how the language parsing rules would change in order to support this, you should post it to the python-ideas mailing list.

If that discussion results in a consensus, then we can re-open this issue. But unless you have a very compelling rationale, I don't expect any language changes here.