All of which begs the question as to who will fund the project.

句中的 which 仍是关系代词，这种用法主要见于非正式文体，which 与 this 或 that 大致同义，用以代替前面提到过的内容，通常的用法应该是：

..., all of which begs the question as to who will fund the project.

但在非正式文体中，有时也将这种非限制性定语从句独立成句，网友的句子就属于这种情况：

All of which begs the question as to who will fund the project. 所有这一切让人想到这样一个问题：谁来为该工程提供资金。（which指代上文提到的情况）

另举几例如下(均摘自词典和语法著作)：

He claimed I was jealous of Elliott. Which was a manifestly baseless accusation. 他断定说我嫉妒艾略特。这显然是毫无根据的指责。

Mary is enormously respected. Which is not to say you are not an exceptionally able lady. 玛丽非常受尊重，但这并是说你不是一位极为能干的女士。

They ran out of drink. Which actually didn’t bother me because I wasn’t drinking. 他们把酒喝完了。但实际上这对我来说无所谓，因为我不喝酒。

As it says in the Bible, my cup is running over. Talking of which, I must get you a cup of tea. 正如《圣经》所说，给我恩赐太多了，我的杯子已经满满当当了。说到杯子，我得去给你倒杯茶来。

网友的句子出自《牛津词典》：