Thanks all for your kind words.
Like Levatio said, it is difficult and expensive to complete the whole series. A few of the series pens have its current premium price in view of its beauty and they are no more in production.
I started with Stockholm and have the opportunity of buying the Berlin at that time. As my favourite colour is blue, I chose Stockholm and promised to get back buying Berlin later. That was year 2001. The price of both pens were half less of the existing M640 series. But the purchase didnt come through and I told myself I could get it some other time may be from the mall or pen shop or the internet etc.
Time passes by, I saw the San Fran, Shanghai and so on in the local market but I just thought these can be obtained easily later. After all its Pelikan.
How wrong I was as when I started my interest to get the whole collection, most of them are sold out already.
I managed to pick up some pelikans here in Kuala Lumpur like Navona, Shanghai, New York, Piccadilly, Grand Place. I am surprised that Chicago was on sale here this year but was informed it was an old stock. As for others I have to hunt them abroad like De la concorde, Madrid, Athens and San Fran.
Again I have to admit, some pens are expensive. Nonetheless, some good buy of the other city pens off set the expensive cost of the pens.
With the final pen ie. Berlin which I got it last Saturday, my dream of achieving the whole series was realised.

Many thanks to DeScribe (Aloysius) whom completed my series with Berlin. (No affiliation but a satisfied customer).
Best regards
Daeng